Voyager GX color mapping

Voyager GX color mapping

[Clemens Koller]

Hello, again,

well, my version of the Silicon Motion SM501 driver works now
quite well on the PowerMac (after some data integrity problems
with the card having in a dusty PCI slot. :-(( )

Only one thing is missing: The color mapping in the
32bit mode doesn't fit with X. The fb memory map has a BGRA
color mapping but X11 writes it in RGBA.

I have tried to change the fb_var_screeninfo.fb_bitfield
values in the driver and via fbset -rgba ... but it seems as
X doesn't care at all.

Where do I need to tweak to get it working?
Is there a performance penalty to remap the pixels in software?
Which is the optimum way to get correct color mapping?

Thank you in advance,

Clemens Koller
_______________________________
R&D Imaging Devices
Anagramm GmbH
Rupert-Mayer-Str. 45/1
81379 Muenchen
Germany

http://www.anagramm.de
Phone: +49-89-741518-50
Fax: +49-89-741518-19


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Re: Voyager GX color mapping

[Geert Uytterhoeven]

On Tue, 14 Dec 2004, Clemens Koller wrote:
> well, my version of the Silicon Motion SM501 driver works now
> quite well on the PowerMac (after some data integrity problems
> with the card having in a dusty PCI slot. :-(( )
> 
> Only one thing is missing: The color mapping in the
> 32bit mode doesn't fit with X. The fb memory map has a BGRA
> color mapping but X11 writes it in RGBA.
> 
> I have tried to change the fb_var_screeninfo.fb_bitfield

You should indeed make sure the fb_var_screeninfo.fb_bitfield values are
correct.  BTW, have you tried fbtest to verify the correctness of your driver?
You can check it out from CVS on SourceForge.

> values in the driver and via fbset -rgba ... but it seems as
> X doesn't care at all.

Fbset wouldn't help here.

> Where do I need to tweak to get it working?

X should obey the fb_var_screeninfo.fb_bitfield values. If it doesn't, it's a
bug in X.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


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Re: Voyager GX color mapping

[Clemens Koller]

Hello, Geert!

>>well, my version of the Silicon Motion SM501 driver works now
>>quite well on the PowerMac (after some data integrity problems
>>with the card having in a dusty PCI slot. :-(( )
>>
>>Only one thing is missing: The color mapping in the
>>32bit mode doesn't fit with X. The fb memory map has a BGRA
>>color mapping but X11 writes it in RGBA.
>>
>>I have tried to change the fb_var_screeninfo.fb_bitfield
> 
> You should indeed make sure the fb_var_screeninfo.fb_bitfield values are
> correct.  BTW, have you tried fbtest to verify the correctness of your driver?
> You can check it out from CVS on SourceForge.

I got fbset already... thanks.

Well, whenever I change the (yet hardcoded) structs in the driver,
fbset -fb /dev/fb2 shows me the correct (changed) values.
But there is no change in X at all if I play around with the values.
Is it possible that X doesn't get my fb_var_screeninfo? Maybe I need
to check xorg.cfg again...
The same things happen in all 32bit (RGBA8888) as well as in
16bit (RGB565) modes (i haven't tried 8bit, as I don't need it).
Is this an PPC-endian related problem?
Is the SM501's BGRA mapping usual?
Hmm...

>>Where do I need to tweak to get it working?
> X should obey the fb_var_screeninfo.fb_bitfield values. If it doesn't, it's a
> bug in X.

Unlikely, I think?

I use a primary "ATI Radeon If" (fb0, fb1) on Depth 16 successfuly.
The SMI501 is the secondary graphics board (fb2) on Depth 16, 24, 32.
Does X listen only to the mapping of the primary card? I guess I will
get offtopic with the X questions.

Clemens Koller
_______________________________
R&D Imaging Devices
Anagramm GmbH
Rupert-Mayer-Str. 45/1
81379 Muenchen
Germany

http://www.anagramm.de
Phone: +49-89-741518-50
Fax: +49-89-741518-19


-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
http://productguide.itmanagersjournal.com/

Re: Voyager GX color mapping

[Geert Uytterhoeven]

On Tue, 14 Dec 2004, Clemens Koller wrote:
> > > well, my version of the Silicon Motion SM501 driver works now
> > > quite well on the PowerMac (after some data integrity problems
> > > with the card having in a dusty PCI slot. :-(( )
> > > 
> > > Only one thing is missing: The color mapping in the
> > > 32bit mode doesn't fit with X. The fb memory map has a BGRA
> > > color mapping but X11 writes it in RGBA.
> > > 
> > > I have tried to change the fb_var_screeninfo.fb_bitfield
> > 
> > You should indeed make sure the fb_var_screeninfo.fb_bitfield values are
> > correct.  BTW, have you tried fbtest to verify the correctness of your
> > driver?
> > You can check it out from CVS on SourceForge.
> 
> I got fbset already... thanks.

I wrote `fbtest', not `fbset' ;-)

> Well, whenever I change the (yet hardcoded) structs in the driver,
> fbset -fb /dev/fb2 shows me the correct (changed) values.
> But there is no change in X at all if I play around with the values.
> Is it possible that X doesn't get my fb_var_screeninfo? Maybe I need
> to check xorg.cfg again...

X may try to change the values again. If you're driver allows that (like it
seem to do, as per your description above), it may become confusion. Please
don't allow to change the bitfields in your driver, only allow the values that
the hardware does support.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
http://productguide.itmanagersjournal.com/

Re: Voyager GX color mapping

[Clemens Koller]

Hi, Geert!

> I wrote `fbtest', not `fbset' ;-)

Okay... I will get it... very soon, tomorrow :-)

>>Well, whenever I change the (yet hardcoded) structs in the driver,
>>fbset -fb /dev/fb2 shows me the correct (changed) values.
>>But there is no change in X at all if I play around with the values.
>>Is it possible that X doesn't get my fb_var_screeninfo? Maybe I need
>>to check xorg.cfg again...
> 
> 
> X may try to change the values again. If you're driver allows that (like it
> seem to do, as per your description above), it may become confusion. Please
> don't allow to change the bitfields in your driver, only allow the values that
> the hardware does support.

Okay... interesting... How does it (try and fail to) change it?
Through IOCTL FBIOPUT_VSCREENINFO? Can I get more debug info out of it?
It's all unread-code-land for me yet. My driver might not implement that
yet... Is there good documentation in addition to RTFC?

Thanks again... I'll keep on learning.

Clemens



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Re: Voyager GX color mapping

[Geert Uytterhoeven]

On Tue, 14 Dec 2004, Clemens Koller wrote:
> > > Well, whenever I change the (yet hardcoded) structs in the driver,
> > > fbset -fb /dev/fb2 shows me the correct (changed) values.
> > > But there is no change in X at all if I play around with the values.
> > > Is it possible that X doesn't get my fb_var_screeninfo? Maybe I need
> > > to check xorg.cfg again...
> > 
> > X may try to change the values again. If you're driver allows that (like it
> > seem to do, as per your description above), it may become confusion. Please
> > don't allow to change the bitfields in your driver, only allow the values
> > that
> > the hardware does support.
> 
> Okay... interesting... How does it (try and fail to) change it?
> Through IOCTL FBIOPUT_VSCREENINFO? Can I get more debug info out of it?

Yes, through FBIOPUT_VSCREENINFO. Your driver should refuse invalid values,
unless it can round them _up_ to make them valid.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
http://productguide.itmanagersjournal.com/

Re: Voyager GX color mapping

[Paul Mundt]

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On Tue, Dec 14, 2004 at 05:40:30PM +0100, Clemens Koller wrote:
> well, my version of the Silicon Motion SM501 driver works now
> quite well on the PowerMac (after some data integrity problems
> with the card having in a dusty PCI slot. :-(( )
> 
Do you have this driver in a tree somewhere? We have a version now in
the sh tree that needs to be tossed out and rewritten, and it would be
good not to duplicate effort..

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Re: Voyager GX color mapping

[Clemens Koller]

Hello, Paul,

>>well, my version of the Silicon Motion SM501 driver works now
>>quite well on the PowerMac (after some data integrity problems
>>with the card having in a dusty PCI slot. :-(( )
 >
> Do you have this driver in a tree somewhere? We have a version now in
> the sh tree that needs to be tossed out and rewritten, and it would be
> good not to duplicate effort..

Currently, it's only local, it's work in progress... PPC tested only.
I did quite some code cleanup and removed some redundant/unused code.
I added some (my first time) module load/unload capability and lots
of test/debug things for HW testing also.

I don't maintain a local CVS tree here yet...
Tell me if I can put it somewhere to the public.

Best greets,

Clemens Koller
_______________________________
R&D Imaging Devices
Anagramm GmbH
Rupert-Mayer-Str. 45/1
81379 Muenchen
Germany

http://www.anagramm.de
Phone: +49-89-741518-50
Fax: +49-89-741518-19


-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
http://productguide.itmanagersjournal.com/